One of the long slender tubes that develop from germinated spores and form the structural parts of the body of a fungus. In many species of fungi, hyphae are divided into sections by cross walls called septa. Each section contains at least one haploid nucleus, and the septa usually have perforations that allow cytoplasm to flow through the hypha. A large mass of hyphae is known as a mycelium, which is the growing form of most fungi. From time to time, hyphae develop reproductive structures that are partitioned from the hypha by holeless septa. In many species, these structures are microscopic; in others, they are visible and large. Mushrooms and shelf fungi are visible reproductive structures of fungi.

Sentence Examples

In Mucor, for example, the end of the primary hypha swells into a spheroidal head (sporangium), the protoplasm of which FIG.

Professor Seward, however, has found a Zygosporites in situ, terminating an apparently fungal hypha: he suggests a possible comparison with the mould Mucor.

Whether a spore results from the sexual union of two similar gametes (zygospore) or from the fertilization of an egg-cell by the protoplasm of a male organ (oospore); or is developed asexually as a motile (zoospore) or a quiescent body cut off from a hypha (conidium) or developed along its course (oidium or chlamydospore), or in its protoplasm (endospore), are matters of importance which have their uses in the classification and terminology of spores, though in many respects they are largely of academic interest.

Appressoria are also formed by some parasitic fungi, as a minute flattening of the tip of a very short branch (Erysiphe), or the swollen end of any hypha which comes in contact with the surface of the host (Piptocephalis, Syncephalis), haustoria piercing in each case the cell-wall below.

Physiologically, any cell or group of cells separated off from a hypha or unicellular fungus, and capable of itself growing out - germinating - to reproduce the fungus, is a spore; but it is evident that so wide a definition does not exclude the ordinary vegetative cells of sprouting fungi, such as yeasts, or small sclerotium like cell-aggregates of forms like Coniothecium.